3D Printing of Spark-Ignited Flame Kernels, Experimentally Captured by 3D-Computer Tomography and Multi-Directional Schlieren Photography

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Yojiro Ishino ◽  
Naoki Hayashi ◽  
Yuta Ishiko ◽  
Kimihiro Nagase ◽  
Kazuma Kakimoto ◽  
...  
Keyword(s):  
Computer Tomography ◽  
High Speed ◽  
Turbulent Flame ◽  
3D Ct ◽  
Ct Reconstruction ◽  
Flame Kernel ◽  
Custom Made ◽  
3D Printed ◽  
Schlieren Photography ◽  
Bottom Left

Non-scanning 3D-CT(Computer Tomography) technique employing a multi-directional quantitative schlieren photographic system with flash light source, has been performed to obtain instantaneous density distributions of spark-ignited laminar / turbulent flame kernels. For simultaneous schlieren photography, the custom-made 20-directional schlieren camera was constructed and used. The concept of the multi-directional shclieren system is shown in top-right figure. Each quantitative schlieren optical system, indicated in top-left figure, is characterized by a rectangular-shaped right source with uniform luminosity. Middle-left picture gives the appearance of the multi-directional schlieren camera. The flame kernels are made by spark ignition for a fuel-rich propane-air premixed gas (flow velocity :1.0 m/s, equivalence ratio :1.4 ). Spark electrodes of 0.4 mm diameter with 1.0 mm gap are used. First, development of laminar flame kernel is indicated in high-speed images of middle-right figure. 3D printed model of the CT reconstruction result (left in bottom-left photograph) shows the spherical shape of flame kernel with a pair of deep wrinkles. The wrinkle is considered to be caused by spark electrodes. Next turbulent flame kernel behind turbulence promoting grid is selected (turbulence intensity 0.26 m/s). The high-speed images of bottom-right figures show corrugated flame shape. 3D model of CT result (right in bottom-left photo.) expresses the instantaneous 3D turbulent flame kernel shapes. These 3D solid models based on 3D-CT reconstructed data of 2 ms, are 3D-printed as 2 times large size for threshold density level of 0.7 kg/m3.

3D Printing of Instantaneous Turbulent Flame Shapes, Experimentally Captured by 3D-Computer Tomography and Multi-Directional Schlieren Photography

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Yojiro Ishino ◽  
Naoki Hayashi ◽  
Yuta Ishiko ◽  
Ili Fatimah Bt Abd Razak ◽  
Yu Saiki ◽  
...  
Keyword(s):  
Computer Tomography ◽  
High Speed ◽  
Turbulent Flame ◽  
Flame Structure ◽  
Turbulent Flames ◽  
Density Level ◽  
Exit Velocity ◽  
Solid Models ◽  
Custom Made ◽  
Schlieren Photography

Non-scanning 3D-CT(Computer Tomography) technique employing a multi-directional quantitative schlieren photographic system(top-left picture) with flash light source, has been performed to obtain instantaneous density distributions of high-speed turbulent flames(for reference, the target flame of 8 m/s exit velocity is indicated in the right-top picture). For simultaneous schlieren photography, the custom-made 20-directional schlieren camera was constructed and used. The target turbulent flame is high-speed flames, anchored on the burner of a nozzle exit of 4.2 mm diameter. The image set of 20 directional schlieren images are processed by MLEM CT-algorithm to obtain the 3D reconstruction of instantaneous density distribution. The solid models(bottom picture) of threshold density level of 0.7 kg/m3 are 3D-printed as 4 times large size for detail observations. The average exit velocity of the propane-air mixture of equivalence ratio of 1.1 is set to be 10, 8, 6 and 4 m/s (models from left to right in the bottom picture). The solid models show the complicated shape of the high speed turbulent flames. The flame structure of higher speed flame has fine scale corrugations. This corresponds to the “corrugated flamelets regime” of the Borghi & Peters diagram well.

Schlieren 3D-CT Reconstruction of Instantaneous Density Distributions of Spark-Ignited Flame Kernels of Fuel-Rich Propane-Air Premixture

2016 ◽  
Author(s):  
Yojiro Ishino ◽  
Naoki Hayashi ◽  
Yuta Ishiko ◽  
Ahmad Zaid Nazari ◽  
Kimihiro Nagase ◽  
...  
Keyword(s):  
Density Distribution ◽  
Light Source ◽  
Optical Systems ◽  
3D Ct ◽  
Ct Reconstruction ◽  
Flame Kernel ◽  
Schlieren System ◽  
Custom Made ◽  
3D Ct Reconstruction ◽  
Schlieren Images

For 3D observation of high speed flames, non-scanning 3D-CT technique using a multi-directional quantitative schlieren system with flash light source, is proposed for instantaneous density distribution of unsteady premixed flames. This “Schlieren 3D-CT” is based on (i) simultaneous acquisition of flash-light schlieren images taken from numerous directions, and (ii) 3D-CT reconstruction of the images by an appropriate CT algorithm. In this technique, for simultaneous schlieren photography, the custom-made 20-directional schlieren camera has been constructed and used. This camera consists of 20 optical systems of single-directional quantitative schlieren system. Each system is composed of two convex achromatic lenses of 50 mm in diameter and 300 mm in focal length, a light source unit, a schlieren stop of a vertical knife edge and a digital camera. The light unit has a flash (9 micro-sec duration) light source of a uniform luminance rectangular area of 1 mm × 1 mm. Both of the uniformity of the luminosity and the definite shape are essential for a quantitative schlieren observation. Sensitivity of the digital cameras are calibrated with a stepped neutral density filter. Target flames are located at the center of the camera. The image set of 20 directional schlieren images are processed as follows. First the schlieren picture brightness is shifted by no-flame-schlieren picture brightness in order to obtain the real schlieren brightness images. Second, brightness of these images is scaled by Gladstone-Dale constant of air. Finally, the scaled brightness is horizontally integrated to form “density thickness images”, which can be used for CT reconstruction of density distribution. The density thickness images are used for CT reconstruction by MLEM (maximum likelihood-expectation maximization) CT-algorithm to obtain the 3D reconstruction of instantaneous density distribution. In this investigation, the “density thickness” projection images of 400(H) × 500(V) pixel (32.0 mm × 40.0 mm) are used for 3D-CT reconstruction to produce 3D data of 400(x) × 400(y) × 500(z) pixel (32.0 mm × 32.0 mm × 40.0 mm). The voxel size is 0.08 mm each direction. In this investigation, the target flame is spark-ignited flame kernels. The flame kernels are made by spark ignition for a fuel-rich propane-air premixed gas. First, laminar flow is selected as the premixed gas flow to establish the spherically expanding laminar flame. The CT reconstruction result show the spherical shape of flame kernel with a pair of deep wrinkles. The wrinkle is considered to be caused by spark electrodes. Next turbulent flows behind turbulence promoting grid is selected. The corrugated shape flame kernel is obtained. The schlieren 3D-CT measurements are made for the complicated kernels. CT results expresses the instantaneous 3D turbulent flame kernel shapes.

scholarly journals 3D patient specific implants for cranioplasty

2019 ◽  
pp. 277-282
Author(s):  
A. Ladaru ◽  
H. Moisa ◽  
A. V. Ciurea
Keyword(s):  
Patient Specific ◽  
Study Cohort ◽  
Cnc Milling ◽  
Ct Reconstruction ◽  
Multi Centre Study ◽  
Patient Specific Implants ◽  
Cranial Defect ◽  
Custom Made ◽  
3D Printed ◽  
Made In

This article presents a multi-centre study cohort study on 50 patients with cranial defects of multiple etiologies (trauma, decompression, tumour surgery, etc.) operated in 10 hospitals. In all patients the neurosurgeon repaired the cranial defect using 3D printed and CNC milling and drilling grafts or Patient Specific Implants, from two world known manufacturers, custom made in accordance with the data obtained from the patient’s 3D CT reconstruction.

Custom Designed Orthodontic Attachment Manufactured Using a Biocompatible 3D Printing Material

2017 ◽  
Vol 54 (4) ◽  
pp. 757-758
Author(s):  
Riham Nagib ◽  
Camelia Szuhanek ◽  
Bogdan Moldoveanu ◽  
Meda Lavinia Negrutiu ◽  
Cosmin Sinescu ◽  
...  
Keyword(s):  
3D Printing ◽  
Treatment Planning ◽  
Computer Tomography ◽  
Volumetric Data ◽  
Impacted Teeth ◽  
3D Printing Technology ◽  
Custom Design ◽  
Custom Made ◽  
Materials Used ◽  
Orthodontic Forces

Treatment of impacted teeth often implies placing a bonded attachment and using orthodontic forces to move the tooth into occlusion. The aim of the paper is to describe a novel methodology of manufacturing orthodontic attachments for impacted teeth using the latest CAD software and 3D printing technology. A biocompatible acrylic based resin was used to print a custom made attachment designed based on the volumetric data aquired through cone bean computer tomography. Custom design of the attachment simplified clinical insertion and treatment planning and 3D printing made its manufacturing easier. Being a first trial, more reasearch is needed to improve the methodology and materials used.

scholarly journals 3D Printed Clamps for In Vitro Tensile Tests of Human Gracilis and the Superficial Third of Quadriceps Tendons

2021 ◽  
Vol 11 (6) ◽  
pp. 2563
Author(s):  
Ivan Grgić ◽  
Vjekoslav Wertheimer ◽  
Mirko Karakašić ◽  
Željko Ivandić
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Tensile Tests ◽  
Biomechanical Properties ◽  
Testing Procedure ◽  
Laboratory Equipment ◽  
Fused Deposition ◽  
Custom Made ◽  
3D Printed

Recent soft tissue studies have reported issues that occur during experimentation, such as the tissue slipping and rupturing during tensile loads, the lack of standard testing procedure and equipment, the necessity for existing laboratory equipment adaptation, etc. To overcome such issues and fulfil the need for the determination of the biomechanical properties of the human gracilis and the superficial third of the quadriceps tendons, 3D printed clamps with metric thread profile-based geometry were developed. The clamps’ geometry consists of a truncated pyramid pattern, which prevents the tendons from slipping and rupturing. The use of the thread application in the design of the clamp could be used in standard clamping development procedures, unlike in previously custom-made clamps. Fused deposition modeling (FDM) was used as a 3D printing technique, together with polylactic acid (PLA), which was used as a material for clamp printing. The design was confirmed and the experiments were conducted by using porcine and human tendons. The findings justify the usage of 3D printing technology for parts manufacturing in the case of tissue testing and establish independence from the existing machine clamp system, since it was possible to print clamps for each prepared specimen and thus reduce the time for experiment setup.

scholarly journals Recurrent contracted sockets treated with personalized, three-dimensionally printed conformers and buccal grafts

2021 ◽  
pp. 112067212110000
Author(s):  
Annabel LW Groot ◽  
Jelmer S Remmers ◽  
Roel JHM Kloos ◽  
Peerooz Saeed ◽  
Dyonne T Hartong
Keyword(s):  
Three Dimensional ◽  
Case Series ◽  
Secondary Outcome ◽  
Retrospective Case ◽  
Upper Eyelid ◽  
Ocular Prosthesis ◽  
Buccal Mucosal Graft ◽  
Custom Made ◽  
3D Printed

Purpose: Recurrent contracted sockets are complex situations where previous surgeries have failed, disabling the wear of an ocular prosthesis. A combined method of surgery and long-term fixation using custom-made, three-dimensional (3D) printed conformers is evaluated. Methods: Retrospective case series of nine patients with recurrent excessive socket contraction and inability to wear a prosthesis, caused by chemical burns ( n = 3), fireworks ( n = 3), trauma ( n = 2) and enucleation and radiotherapy at childhood due to optic nerve glioma ( n = 1) with three average previous socket surgeries (range 2–6). Treatment consisted of a buccal mucosal graft and personalized 3D-printed conformer designed to be fixated to the periosteum and tarsal plates for minimal 2 months. Primary outcome was the retention of an ocular prosthesis. Secondary outcome was the need for additional surgeries. Results: Outcomes were measured at final follow-up between 7 and 36 months postoperatively (mean 20 months). Eight cases were able to wear an ocular prosthesis after 2 months. Three cases initially treated for only the upper or only the lower fornix needed subsequent surgery for the opposite fornix for functional reasons. Two cases had later surgery for cosmetic improvement of upper eyelid position. Despite pre-existing lid abnormalities (scar, entropion, lash deficiency), cosmetic outcome was judged highly acceptable in six cases because of symmetric contour and volume, and reasonably acceptable in the remaining two. Conclusions: Buccal mucosal transplant fixated with a personalized 3D-designed conformer enables retention of a well-fitted ocular prosthesis in previously failed socket surgeries. Initial treatment of both upper and lower fornices is recommended to avoid subsequent surgeries for functional reasons.

scholarly journals 3D-Printed Connector for Revision Limb Salvage Surgery in Long Bones Previously Using Customized Implants

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 707
Author(s):  
Jong-Woong Park ◽  
Hyun-Guy Kang ◽  
June-Hyuk Kim ◽  
Han-Soo Kim
Keyword(s):  
Limb Salvage ◽  
Salvage Surgery ◽  
Revisional Surgery ◽  
Limb Salvage Surgery ◽  
Musculoskeletal Tumor ◽  
Musculoskeletal Tumor Society ◽  
Proximal Ulna ◽  
Custom Made ◽  
Orthopedic Oncology ◽  
3D Printed

In orthopedic oncology, revisional surgery due to mechanical failure or local recurrence is not uncommon following limb salvage surgery using an endoprosthesis. However, due to the lack of clinical experience in limb salvage surgery using 3D-printed custom-made implants, there have been no reports of revision limb salvage surgery using a 3D-printed implant. Herein, we present two cases of representative revision limb salvage surgeries that utilized another 3D-printed custom-made implant while retaining the previous 3D-printed custom-made implant. A 3D-printed connector implant was used to connect the previous 3D-printed implant to the proximal ulna of a 40-year-old man and to the femur of a 69-year-old woman. The connector bodies for the two junctions of the previous implant and the remaining host bone were designed for the most functional position or angle by twisting or tilting. Using the previous 3D-printed implant as a taper, the 3D-printed connector was used to encase the outside of the previous implant. The gap between the previous implant and the new one was subsequently filled with bone cement. For both the upper and lower extremities, the 3D-printed connector showed stable reconstruction and excellent functional outcomes (Musculoskeletal Tumor Society scores of 87% and 100%, respectively) in the short-term follow-up. To retain the previous 3D-printed implant during revision limb salvage surgery, an additional 3D-printed implant may be a feasible surgical option.

scholarly journals Additively Manufactured Parts Made of a Polymer Material Used for the Experimental Verification of a Component of a High-Speed Machine with an Optimised Geometry—Preliminary Research

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 137
Author(s):  
Artur Andrearczyk ◽  
Bartlomiej Konieczny ◽  
Jerzy Sokołowski
Keyword(s):  
Polymer Material ◽  
High Speed ◽  
Numerical Models ◽  
Flow Analysis ◽  
Experimental Tests ◽  
Strength Analysis ◽  
Compressor Wheel ◽  
Operational Characteristics ◽  
3D Printed ◽  
Novel Method

This paper describes a novel method for the experimental validation of numerically optimised turbomachinery components. In the field of additive manufacturing, numerical models still need to be improved, especially with the experimental data. The paper presents the operational characteristics of a compressor wheel, measured during experimental research. The validation process included conducting a computational flow analysis and experimental tests of two compressor wheels: The aluminium wheel and the 3D printed wheel (made of a polymer material). The chosen manufacturing technology and the results obtained made it possible to determine the speed range in which the operation of the tested machine is stable. In addition, dynamic destructive tests were performed on the polymer disc and their results were compared with the results of the strength analysis. The tests were carried out at high rotational speeds (up to 120,000 rpm). The results of the research described above have proven the utility of this technology in the research and development of high-speed turbomachines operating at speeds up to 90,000 rpm. The research results obtained show that the technology used is suitable for multi-variant optimization of the tested machine part. This work has also contributed to the further development of numerical models.

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